Demon within
by azure flame knight12
Summary: Kenshii Sendou is Yukari's older brother but he chose a different way of life. The way of the Ninja. He also has a demon sealed inside of him and his seal is weakening each passing day. So Tsundade sends him to see a old friend of the 3rd Hokage which is the head master of Yokai academy. Will he be able to beat the demon within or will it take control? Rated T.
1. Chapter 1

_How_ is everyone? I was reading some of my old stories i found on a USB and i got a idea for a Rosario+Vampire and Naruto story which is this one. I hope you all enjoy it. Thanks for taking the time and reading. Thanks to my co-author mercwiththemouth. this is my first Naruto and Rosario+vampire crossover so i don't know how it turned out.

I don't own Rosario+vampire or naruto

speech

_thoughts._

Now sit back and enjoy the story.

* * *

Everyone knows that Witches are border beings. Not quite monsters and not quite humans. What people don't know is that there is another race like Witches. But they are stronger and faster. Witches focus on training mental and spiritually. The second race, Ninjas, focus on training their physical body, mental and spiritually. If Witches have enough power and determination, they too could be a Nin as well. However, they have it tougher and need more training. But that hasn't stopped many from trying to become one.

* * *

Tsukune Aono head shot up when he heard a loud thump on the board echoed in the room. He looked in front of him and saw the teacher, Ms. Neknome, wearing her normal thin strip shirt, short skirt and her usual smile. He felt eyes on him and heard some quiet chuckles and giggles. One of the giggles came from beside him where a long pink hair girl wearing the female version of the uniform sat. The uniform was a green jacket, skirt, a white shirt and red tie. Tsukune wore the male version of it, which was the same just with khaki pants.

"Your homework is to do a report about the Ninjas and their way of life. That's all for today." Ms. Neknome said with a smiling.

The class got up and started to leave the room while Tsukune yawned before gathering his things up and the pink hair girl walked up to him.

"Couldn't sleep last night?" She asked.

"I was up late finishing homework. I'll be fine after a nap Moka." He replied.

"Looked like you were getting a good one earlier." Another girl said as she walked up to them. She wore the school skirt a white sweater, yellow vest with a red ribbon. She had light blue hair with a ribbon tied around it to make a small ponytail and purple eyes. What most people notice about her at first are her huge breasts.

"You have no room to talk Kurumu." A cool voice said behind Tsukune. He jumped and turned around and saw a girl peeking over a desk at him. She had purple hair and deep blue eyes and a sucker in her mouth. She wore a white hoodie with the shoulders down to reveal the shoulder strips of a black top. She had black and purple socks on that went up her legs. A belt on her left leg and the school skirt.

"How long have you been there Mizore?" Moka asked.

"Since class started." She replied.

Tsukune walked out of the classroom with Moka, Kurumu and Mizore following. A small girl about 13 ran up to them wearing the clothes of a witch and the school skirt.

"Hey Yukari." Tsukune said to the girl.

"Hey Tsukune." She said to him as she joined the group and they walked down the hallway.

"When Ms. Neknome was talking about Ninjas it started to make me wonder how strong can they be?" Moka asked.

"Well their border beings so I don't think very strong." Kurumu said.

A golden pan fell on top of her head knocking her to the ground and they looked to see Yukari holding her heart shape wand and a tick mark on her forehead.

"For your information there are Ninja that can hold their own against vampires." Yukari said.

Moka, Mizore and Tsukune looked at her shocked.

"Are you serious?" Tsukune asked.

Yukari nodded before looking at them.

"The Ninja are divided into ranks and the rank ANBU and some Jonin can fight vampires."

"You seem to know a lot about Ninja." Moka said.

"Well she is a genius." Tsukune said.

Yukari blushed a little and shook her head.

"That's not how I know about Ninja."

"Then how do you know about them?" Mizore asked.

"My older brother Kenshii is a chunin."

They all looked at her shocked even Kurumu who just recovered looked at her.

"You have an older brother?" Tsukune asked.

"Why are you just telling us this?" Moka asked.

"I haven't seen him in two years. We write to each other through. At first no one thought he could be a ninja."

"What do you mean?"

"His magic was weak."

"In other words he could barely do magic." Mizore said.

"Yea that's right. But he was determined to become a ninja so he trained hard. Papa use to say he would have to go and get Kenshii because he would be too exhausted to move."

"Did he manage to get stronger?" Kurumu asked.

"Well duh if not he wouldn't have been able to become a ninja. When he became a ninja. It seem like it was second nature to him."

"He was that good?" Tsukune asked and Yukari nodded.

"He was one of the best but after something happened he started to slip."

"What happened?" Moka asked.

"I don't know. He wouldn't tell me. All he said was it changed him."

They walked down the hallway each lost in their thoughts.

* * *

In Konoha, the merchants were busy selling their goods and people walked up and down the streets talking. The Hokage monument loomed behind the Hokage's office. The faces of the past Hokage's watch the people as if guarding them. In an apartment slept a light brown hair guy his arm hung off the bed as he snored lightly. If anyone was close to the apartment they could have heard paws crossing the wooden floor of the apartment. Something sniffed the guy's hand before nudging it. The guy pulled his arm under the cover before cracking his purple eyes and sitting up in the bed yawning. He laid back down but he didn't get a chance to doze off when he felt something flip him out of his bed. He hit the floor with a thud. He sat up looking on the other side of the bed and saw a full grown bear sitting there looking at him. It had grey fur with a white collar of fur around its neck. It had a collar with the village symbol, which was a leaf, around its neck. It looked at the guy with its black beady eyes.

"What's the big idea?" He asked.

The bear looked at him before turning and looking at the refrigerator before looking back at him.

"Ah of course you're hungry." He said as he stood up and walked towards the refrigerator with the bear following.

He opened it and pulled out a four uncooked steaks before putting them on the ground for the bear to eat.

"If I'm not careful you're going to get spoiled on those steaks Ursa." The boy said scratching the bear's head.

The door opened and a blond spike headed boy wearing an orange and black jacket with black pants and a headband with a metal plate and a leaf engraved on it. The blonde hair boy looked at the brown hair one and saw he was still in his sleep pants.

"You slept in Kenshii?" the boy asked a little surprised.

"I would still be asleep Naruto if someone didn't wake me up wanting food." Kenshii said as he looked at Ursa who looked like he had a satisfied smirk on his face.

"Anyway granny Tsunade wanted to talk to you about something." Naruto said.

"I wonder what it is." Kenshii said thinking.

"Hey! Maybe you're getting promoted to Jonin!" Naruto said excited.

Kenshii laughed a little before looking at Naruto.

"I wish. I doubt that though after what i did."

"Why did you do it though? I mean you could have died."

"Naruto what I did was completely crazy, idiotic and suicidal. I see that now but when I tried, I was just trying to gain power. I won't try that again. May not get lucky again and death doesn't let getting cheated twice. "

Kenshii sighed and went to get ready. He passed the bathroom and walked in to look at himself in the mirror mostly a mark he head on his chest over his heart. It was a seal, he felt it as it grew weaker each passing day. Kenshii walked to his bedroom and got a black sleeveless shirt, black ninja pants and a arm band with the leaf symbol engraved on a metal plate on it. He also had the leaf symbol tattooed on his shoulder. He walked out of the bedroom and towards the front door with Ursa following. He looked around and saw Naruto was already gone.

"_That guy has a hard time staying in one spot for too long."_ He thought as he shut the door and locked it before walking towards the Hokage's office with Ursa following him.

* * *

The Hokage's office always surprised him at how big it was. At a desk sat a woman with long blonde hair in twin pigtails a blue diamond on her forehead. She wore a white shirt and a dark green over cloak. She looked up from the paper work she was doing when she heard the door open.

"You wanted to see me Lady 5th?" Kenshii asked.

"Yes I did, come here." She said standing up and walking around her desk.

He did as she told him and she lifted his shirt to look at the seal.

"How is it?"

"I feel it fading but it's holding."

"I was afraid of that." She said putting his shirt down.

"Yea Sensei Anko tried her best."

"But seals aren't her strong point. So I got in contact with a friend of the 3rd Hokage that may be able to help you." Tsunade said as she sat back down.

Kenshii looked at her surprised.

"Really?"

"Yes and he said he would take a look and see what he can do."

"But can he really help me?"

Tsunade sighed and looked at Kenshii.

"Listen to me Kenshii there are more than one way to deal with a demon. However I want you to give me your word on one thing."

"What is that?"

"Never and I mean Never use the demon's powers unless you have no choice too."

"Of course."

"Also don't do anything rash like you usually do. Now go get ready you're heading out for Yokai academy in a hour."

Kenshii looked at her his eyes wide.

"Did you say Yokai academy?"

"Yes I did. Why?"

Suddenly Kenshii did a backflip and both Tsunade and Ursa looked at him confused.

"My little sister goes there. It's been two years since I last saw her."

Kenshii saluted before running out of the office with Ursa following him. Tsunade watched him leave before turning and looking out the window towards the Hokage faces.

"Well Kenshii you're chance of beating your inner demon just went from none to slim." She said to herself.

* * *

Three days later at Yokai academy Yukari got a letter. She walked down the path that led to the school reading it. When she got to the last sentence her eyes widen and she smiled letting out a yell of happiness. People looked at her as if she lost her mind when Moka and her other friends walked up to her.

"What are you yelling about?" Kurumu asked.

Yukari looked at her friends before glomping Tsukune in a hug.

"What's got you so happy Yukari?" Moka asked.

"My brother is coming here to the academy!" She said.

Her friends eyes widen and each one lost in their own thoughts.

"_I wonder how stealth a ninja can be."_ Mizore thought.

"_I hope he's nice." _Outer Moka thought.

"_I hope he gives me a challenge._" Inner Moka thought.

"_I wonder if he's like Yukari here. I hope not."_ Kurumu thought.

"_I'm so dead."_ Tsukune thought as he gulped in nervousness.

* * *

Well there you have it everyone. I hope you like it. I know it's short and if i keep working on the story i'll make the chapters long i promise. a lot of people enjoy it i'll keep writing on it. Keep in mind this is my first Rosario+vampire and Naruto crossover so be nice please? Please tell me your thoughts and comments so i know if i should keep working on this story. Thanks for taking the time and reading.


	2. Chapter 2

Hey everyone i'm back with the second chapter for demon within. Thanks for reading and i hope you enjoy the chapter. Thanks to my co-author mercwiththemouth.

I don't own Rosario+Vampire or Naruto.

normal speech

_thoughts_

**Inner MOka**

now without further ado sit back and enjoy the story.

* * *

A week later, a boy stood in the headmaster's office. He wore black pants with a pouch full of Kunai and Shurikens. Scrolls were attached on a belt on the back of his pants and a mask with a bear pattern on the side. He had a black sleeveless shirt on. An armband with a metal plate with a leaf engraved in it. The same leaf tattooed on his arm. He had light brown hair and purple eyes. Beside him on the ground laid a bear. He looked around the office noticing all sorts of old artifacts and old books in languages he never saw before. A chuckle that came across a desk got his attention. He turned to look and saw a man with glowing eyes wearing white priest robes and holding a rosario. He looked the boy over and grinned.

"So you're the one Tsunade told me about Kenshii Sendou." He said.

"Yes sir that's me." Kenshii said.

"I can sense the seal on you weakening."

"That's what I was afraid of sir."

The man's grin widened.

"I can teach you how to control it."

Kenshii looked at him in surprise.

"You can teach me?"

"Of course I can. However, I don't know if you'll be strong enough. Therefore, I'll give you a test to see if you're strong enough."

Kenshii looked at him waiting for the test.

"It's a simple survival test. There is a vampire on campus named Moka Akashiya. If you can keep standing after a five minute battle with her then I'll know you're strong enough for me to teach."

Kenshii nodded and put the mask on before looking at the bear.

"Let's go Ursa." He said

Ursa stood up and stretched before following Kenshii.

* * *

Tsukune walked down the path to the main school building noticing all the adults walking around. He started to wonder why all the adults were around when he remembered. It was parent's day. He started to panic on the inside.

"Ah great I got to deal with Kurumu's mother and Mizore's." He said aloud.

He felt a presence behind him and he turned around expecting to see Mizore or her mother but was surprised to see a guy about his age wearing a mask with a bear pattern on it. What unnerved him the most was the big grey bear standing beside the mysterious guy.

"Do you know a Moka Akashiya?" The mysterious guy asked.

"Moka? Yea I know her why?" Tsukune asked nervously.

"I would like her to spar against someone."

"Who would that someone be?"

"Me."

"Why spar with you?"

"I'm afraid I can't say. Will you tell her or should I find her myself."

"Yea I'll tell her."

"I thank you. I'll be at the field."

The mysterious guy bowed before he and the bear that was with him vanished right in front of Tsukune. Tsukune stood there for a minute trying to figure out if what he saw actually happen before he ran towards the main building to find Moka.

* * *

In the classroom Moka, Kurumu and Mizore stood by watching a woman with long dark blue hair wearing a dress and jacket arguing with a woman with purple hair a sucker in her mouth and wearing a kimono.

"How many times will I have to say it? Tsukune is going to be my son-in-law." The blue hair woman said.

"You were always disillusion Ageha. But I'll still let you come to Tsukune's and Mizore's wedding." The woman in the Kimono said.

"What was that Tsurara?" Ageha said as her nails grew longer.

"Here we go again." Kurumu said as she sighed.

"Think we should stop them before they hurt someone?" Moka asked.

Mizore just stood there watching; when the door open and Tsukune ran in out of breath.

"Tsukune what is it?" Mizore asked.

He held up a finger to tell them to give him a minute to catch his breath.

"I just ran into a guy who wanted to fight Moka." Tsukune said.

Moka looked at him with her eyes widen.

"Why would he want to do that?" Moka asked

"I don't know but it felt like he knew how to fight. Plus he had a bear with him."

"He had a living bear with him?" Kurumu asked surprised.

"Yea but it seemed tamed. It didn't attack anyone and it stood beside him."

"Tsukune." Ageha said.

He turned to look at her and Tsurara.

"What is it Ms. Kuruno?"

"Can you describe what this person looked like?"

"Not really he wore a mask with a bear pattern on it."

Tsurara raised an eye brow.

"Did he have a marking on him?"

Tsukune started to think a minute.

"Now that you mention it he did have a tattoo of a leaf on his arm and the bear had the same leaf on a collar."

"I thought so." Tsurara said.

"What do you mean mom?" Mizore asked

"That person Tsukune ran into was a Ninja from Konoha."

"And I bet you that bear that Tsukune saw him with was a summoning." Ageha said agreeing with Tsurara.

"So a ninja challenged Moka?" Tsukune asked looking at Moka.

"Why would he do that?"

"He wouldn't say why." Tsukune said thinking.

"Where is he at?" Moka asked Tsukune.

"He said he'll be waiting at the field."

Moka started to walk towards the door.

"Where are you going?" Kurumu asked.

"I'm going to the field." Moka said as she walked out the door and into the hallway.

"Moka I get the feeling this is a bad idea!" Tsukune yelled following her.

"I got to see this fight." Kurumu said as she too followed.

Mizore said nothing as she followed also with Ageha and Tsurara walking behind them. Yukari and her parents saw her friends run past and she looked in the direction they ran.

"I wonder where they are going." Yukari said to a man with light brown hair wearing a sweater, brown pants, and glasses. Beside him stood a woman with light brown hair to her shoulders wearing witch clothes.

"Seems like there is a visitor here and he wants to challenge Moka to a fight." Ageha said as she walked up to them.

"A visitor? Who?" Yukari asked ready to fight if she needed to.

"A Konoha Ninja."

Yukari's eyes widen when she heard ninja.

"I wonder…" Yukari said before running after her friends leaving their parents to follow.

* * *

At the field Moka saw the mysterious guy sitting in the middle of the field and it looked like he was meditating. He looked up at her before standing up his eyes never leaving her.

"Moka Akashiya?" He asked.

"Yes I am. Who are you?"

The guy reached up and removed his mask.

"My name is Kenshii Sendou and I would like to spar with you." He said bowing to Moka.

"But why?"

"I can't explain right now but know this."

"Know what?"

"My life and everyone else's is riding on this battle. So fight like you're life depends on it. Since it does."

They heard a chuckle to the side and saw the head master standing to the side with Moka's friends who were nervous. All except Yukari and her parents who looked surprised.

"Kenshii!" Yukari yelled.

"Begin!" the headmaster said.

Moka was too busy looking at her friends to notice Kenshii as he ran towards her.

"Never look away from your opponent Moka-san." He said as he tried to punch her.

But she quickly turned and crossed her arms to block it but it still pushed her back a foot. He quickly stood on his hands and tried to kick Moka but she kicked towards his hands and sent him into the dirt face first before kicking him away. As soon as he stopped sliding he jumped back to his feet looking at Moka as if studying her.

"His recovery speed is impressive." Mizore said.

"I get the feeling he's not even fighting seriously." Ageha said.

"Know you're opponents' weakness." Kenshii said looking at Moka.

"What do you mean?" Moka asked.

Kenshii did some hand movement and Moka watched curiously but it soon turned to fear when she saw the spire of water that surrounded him.

"Water style: Water dragon jutsu." Kenshii said.

As soon as he was finished the spire of water turned into a dragon made out of water and rushed towards Moka. She managed to jump out of the way before it hit where she stood. The water started to fall as if it was rain and Moka started to feel pain as the water hit her.

"Hey that's cheating!" Kurumu yelled.

"Not really." Tsurara said.

"What do you mean?"

"He was taught to use an opponent's weakness whenever he can." The headmaster said.

Moka tried to move but every time she did, pain shot through her body. Kenshii reached into his pouch and pulled out a kunai before running towards Moka. Tsukune watched terrified when he felt something behind him. He turned around and saw the bear looking right at him. It looked him in the eyes before the bear ran towards Tsukune and tackled him to the ground making Tsukune slide towards Moka and making the others look at it in surprised.

"Where did that bear come from?" Yukari asked.

The headmaster chuckled and looked at Yukari.

"It's been asleep behind us the whole time." Ageha said.

Tsukune stopped sliding beside Moka and he stood up.

"Tsukune! Take off my rosario quick!" Moka said.

Tsukune stood up and looked at the bear.

"You knew didn't you?" Tsukune asked looking at the bear before grabbing Moka's rosario and pulling it off.

A dark energy came from Moka as her hair turned sliver, her breasts and butt a few inches and her green eyes turned red while she gained slit pupils. Tsukune hurried back to the side holding Moka's rosario while Moka and Kenshii faced each other.

"So I was right. You were holding back." Kenshii said.

"**I'll admit I never thought you would be this strong."** Moka said.

"I get that a lot. Now the kid gloves come off."

Kenshii touched a small round circle on his wrist, a puff of smoke appeared in his hand, and when the smoke cleared a giant shuriken was in his hand.

"What the hell?-!" Kurumu asked shocked.

"Where did that come from?-!" Tsukune asked in the same shock as Kurumu.

"Moka needs to be careful with that weapon." Tsurara said.

"Why's that?" Mizore asked.

"There's a summoning on the weapon." Yukari said watching the fight closely.

"_Why is he doing this? He would never challenge someone like this."_ Yukari thought.

She looked at her parents and notice they were thinking the same thing.

"Now the real fight begins Moka-san!" Kenshii yelled throwing the shuriken at her. As he threw it his hand got cut and three drops of blood got on the shuriken.

Moka got ready to dodge but her eyes widen when she saw the weapon disappear in a puff of smoke and she jumped backwards avoiding something that crashed down where she was standing. The dirt cleared and her friends saw a was a pitch black bear with a chain wrapped around its body and a red marking through its left eye that looked like a scar. Its claws were longer and sharper than any other.

"That bear looks evil." Mizore commented.

"Yes he does but he's not. He was breed for fighting." The headmaster said.

"His name is Grizz. He's not my first choice in a summoning but he gets the job done." Kenshii said.

The bear looked back at him and huffed.

"Nice to see you too Kenshii." It said.

"The bear talked!" Yukari said in complete shock.

Everyone except the headmaster, Ageha, Tsurara and Yukari's parents where speechless.

"Of course it did. It's a summoning." Ageha said.

"So you're my opponent eh?" Grizz said looking at Moka.

In the blink of an eye Grizz was inches from Moka. He raised his claw up ready to slash down at Moka but she sidestepped and it got the side of her jacket. She kicked at Grizz who went flying backwards but before he got too far away Grizz grabbed the chain it had around it's body in its mouth and threw it at Moka. The chain wrapped around Moka's arm and she was dragged along as Grizz flew. Kenshii appeared on the chain with a small sword in his hand. Moka drug her feet into the ground stopping and forcing Kenshii to fall off the chain dropping his sword in the process. Moka used all her strength to sling Grizz into the Kenshii and knocking him to the ground. Grizz disappeared in a puff of smoke and Kenshii stood up grinning at Moka.

"Not bad. Didn't see that coming that's for sure." Kenshii said.

"**Is that all you got?"** Moka asked with a smirk.

"Nope it's not."

"**What?"**

"My friend Shino once said 'always have an ace in the hole'."

"**What's your 'ace in the hole'?"**

Kenshii did some hand signs and he disappeared in a puff of smoke. When the smoke cleared Moka's eyes widen as did everyone else's. Right in front of her there was at least 50 Kenshii's.

"Bravo Kenshii." The headmaster said grinning and chuckling a little.

"How did he do that?" Kurumu asked

"I'm not sure. I never saw that technique before." Ageha said.

"It's a technique called shadow clone jutsu. To be able to use it a Ninja has to have great chakra control." Tsurara explained.

"How do you know that mom?" Mizore asked looking at her.

"Well I may have dated a Ninja or two when I was younger." Tsurara said with a grin.

"I'll give you a tip Moka." Kenshii said.

"**What's that?"** Moka asked looking at the Kenshii's.

"If you find the real one the clones will disperse. Think of it like a deadly game of hide and seek."

The Kenshii's rushed towards Moka at the same time. She kicked one into three others and all four disappeared into a puff of smoke and she side stepped two making them headbutt each other and disappearing also. That's when she notice the one lone Kenshii that kept away from the pack.

"**Found you!"** Moka said.

The Kenshii pointed at himself and Moka ran towards him.

"Oh shi-" The Kenshii said before Moka's foot connected and to her surprise he disappeared in a puff of smoke.

She turned to look at the Kenshi's that remained and smirked.

"**Clever, Mixing yourself in with the clones."** Moka said.

"Of course only a complete moron wouldn't do that." Kenshii replied before charging at her again.

Tsukune and the others lost sight of Moka as the Kenshii's surrounded her and started to attack. Moka felt the wind of a Kunai that just missed her ear and she kneed the Kenshii when she did the others disappeared and she spun around sending him flying across the field and he landed on the ground making a dirt cloud raise up.

"**It's over."** Moka said trying to regain her breathe.

She was beat up but not as badly as they thought she would be. She had mostly cuts and bruises. She started to walk away but she stopped and her eyes widen and she turned to where Kenshii landed.

"_What was that just now? That power I felt for a second it felt demonic." _She thought.

To her surprise and to the others Kenshii stood back up shakily. He had cuts and bruises with a small trail of blood running down his forehead. Moka could tell he was barely conscious. His shirt was tore a little bit and when Yukari say a black mark on his chest she gasped.

"What is it Yukari?" Tsukune asked.

"That mark under his shirt…" Yukari said in fear.

"What about it?" Kurumu asked only seeing a little bit of the mark.

"It's part of a seal." Yukari said forcing her eyes back to look at Kenshii.

"_What did you do to yourself Kenshii?"_ She thought.

"You're wrong Moka-san." Kenshii said standing up his hair covering his eyes.

"**What do you mean?"** Moka asked.

"A battle isn't an argument." Kenshii said as a gentle wind blew his hair revealing his eyes.

Moka's eyes widen a little more when she saw his eyes turned red with a part of a Yin and Yang in it. From what she could tell it was the Yin part.

"As long as there is a person standing in a battle it will never be over."

Kenshii pulled out a kunai as he got ready to rush at Moka. For some reason Moka couldn't move. She looked down and saw she stepped in the middle of a binding spell. She looked up at Kenshii as he ran towards her.

"That's enough!" The headmaster yelled.

Both Moka and Kenshii looked at him as he grinned at Kenshii.

"You passed Kenshii. I'll help you but for now rest."

Kenshii put the Kunai away and the binding spell ended. Kenshii bowed to Moka before he passed out and landed on the ground out cold. Yukari and her parents ran towards Kenshii to check up on him while Tsukune, Kurumu and Mizore walked towards Moka. But she didn't pay any attention because her mind was on that demonic power she felt for a split second.

"_It came from Kenshii didn't it?"_ She thought to herself as she looked at him.

* * *

There you have it everyone. I hope you all enjoyed the chapter. Please tell me you're thoughts in the comments. Thanks for taking the time and reading. Til next time


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